The optical communication connection mode between a BBU (Base Band Unit) and a RRU (Remote Radio Unit) of a current eNB is mainly a direct connection mode, whose connection number mainly depends on the optical interfaces provided by the RRU and the BBU. With the development and application of optical technology and optical switching network, the diversification of communication modes between the BBU and the RRU of the eNB is being realized instead of the single direct connection mode, i.e., the BBU and the RRU of the eNB use an optical network for communication, which is one of relatively popular hot topics in the communication field. The optical communication connection mode between the BBU and the RRU of the eNB is the direct connection mode, which has the following shortcomings:
1. The communication connection mode lacks diversification, and networking is single. Since the optical communication connection mode between the BBU and the RRU of the current eNB is mainly the direct connection mode, the networking thereof is limited especially in a region whose physical terrain is complicated, which further affects the application thereof.
2. The optical communication links between the BBU and the RRU of the eNB are limited. The optical communication links between the BBU and the RRU of the current eNB are mainly based on the optical interfaces provided by the RRU and the BBU, and therefore the connection number is limited.
3. Transmission distance is limited. The transmission distance between the BBU and the RRU of the eNB in the direct connection mode is merely M km (wherein M>0), and can not be enlarged to a distance such as [M, 2M] or even longer.